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the alveolar wall fenestrations to reach the medullary cavities of the alveolar bone (Garfunkel etal.1983).

2) Along the outer surface of the alveolar bone, below the

periosteum and crossing through the cortical cavities to the medullary cavities of the alveolar cancellous bone (Tagger etal.1994a; Tagger etal.1994b).

In both cases, the anesthetic penetrates the medullary cavities of the alveolar cancellous bone (Fuhs etal. 1983; Dreyer et al. 1983; Garfunkel et al. 1983; Smith and Walton1983b; Tagger etal.1994a,1994b), thus infiltrating wide areas of the bone under pressure and moving toward the apex at some distance from the injection site (Garfunkel etal.1983; Smith and Walton1983b). Furthermore, as it reaches the vessels and capillaries of the medullary cavities, it is considered to be equivalent with an intravascular injection (Smith et al. 1983c; Rawson and Orr II 1985; Pashley 1986), although experiments in humans have found that, compared with intravascular injection, blood levels are 25–40% without a vasoconstrictor, 10–15% with epinephrine, and 10–50% with felypressin (Cannell etal.1993). In summary, the PDL technique functions in much the same way as the intraosseous technique (Garfunkel etal. 1983; Smith and Walton 1983b; Smith et al. 1983c; Pashley 1986), but with lower levels of anesthetic.

Factors that Determine Efficacy

Major Factors

1) The pressure exerted is essential for successful anesthesia.

Resistance during injection is highly indicative of successful anesthesia (Walton and Abbott1981; Smith and Smith1983a) because the pressure is necessary for the anesthetic solution to be distributed along the periodontal ligament and bone marrow to reach the apex (Edwards and Head1989).

2) Use of pressure syringes (pistol- type). This type of syringe

is more successful than traditional cartridge-

type syringes (Table18.1), thus reinforcing point 1 above. This point reinforces the first point, since pressure syringes are designed to exert more pressure during the injection (Pashley1986; D’Souza etal.1987; Walmsley etal.1989), to the extent that it is almost double (Table18.2).

3) Use of local anesthetic solutions with epinephrine. The

best results are observed with standard solutions of lidocaine 2% with epinephrine 1:100

000 (Malamed1982; Johnson etal.1985; Kim1986; Schleder etal.1988) and 1:80

000 (Gray and Rood 1987; Meechan 2002), and

articaine 4% with epinephrine 1:100

000 (Berlin

etal.2005).

Lidocaine 2% with epinephrine 1:50 000 (high concentration of epinephrine) also yields favorable results, which are even better and last longer than pulpal anesthesia, although they also increase the risk of adverse effects (such as tachycardi, palpitations, or tremors) (Kaufman etal.1984). This better result is due not only to the fact that the vasoconstrictor retains the anesthetic by preventing its absorption, but also to the fact that epinephrine partially reduces blood flow in the dental pulp, thus leading to a partial reduction in A delta nerve fiber impulses (Edwards and Head1989).

Poorer results are observed with anesthetic solutions that do not contain epinephrine (Malamed 1982; Kaufman etal.1984; Kim1986; Gray and Rood1987; Meechan2002), have low doses of epinephrine (1:200

000), or contain weaker vasoconstrictors (norepinephrine, levonordefrin, felypressin) (Malamed 1982; Kaufman etal. 1984,1994; Johnson etal.1985).

Minor Factors

1) Treatments where efficacy is evaluated.

● The best results are observed with extractions, obtu-

rations, and periodontal procedures (Malamed1982;

Table18.1 Percentage ofsuccess withintraligamentary (periodontal ligament technique) anesthesia achieved withhigh- pressure

syringes (pistol- grip) or traditional cartridge syringes.

Reference High- pressure syringe Standard syringe Treatment

Malamed (1982) 89% (54/61) 82% (32/39) Ob, En, Ex, C Smith and Walton (1983b) 65% (39/60) 62% (55/88) En D’Souza etal. (1987) 72% (13/18) 50% (12/24) Cold Proportion 75% 65%

Ob, obturation; En, endodontics; Ex, extraction; C, cutting. Cold, dry ice stimulation.

=3.9537(P < 0.05).

Success (proportion)

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Table18.2 Maximum pressures achieved withstandard high- pressure syringes (pistol- type) inthe PDL andinfiltrative techniques.

Pressure

Factors evaluated PSI kg/cm

Maximum pressure achieved Anesthetic technique Type of syringe PDL Traditional 340 23.9 Pashley etal. (1981)

Traditional 325 22.8 Walmsley etal. (1989) The Wand 232 16.0 Nusstein etal. (2005a) The Wand STA High-

pressure 616 43.3 Walmsley etal. (1989)

Infiltrative Traditional 153 10.8 Maita and Horiuchi (1984)

The Wand STA Palatal injection The Wand STA Mandibular block The Wand STA Cartridges: resistance to breakage

Glass 1474 101.2 Meechan etal. (1990)

Plastic 655 45.2 “

kg/cm2, kilograms per square centimeter; PDL, periodontal ligament; PSI, pounds per square inch. 1 kg/cm2=14.5PSI; 1PSI=0.069kg/cm2.

The Wand STA injection 0.005 ml/second, mean pressure values.

294 20.3 Hochman etal. (2006)

11.5 0.8 Hochman etal. (2006) 68 4.7 Hochman etal. (2006)

5 0.35 Hochman etal. (2006)

Reference

Faulkner 1983; Kaufman et al. 1983; Miller 1983; Grundy 1984; Gray and Rood 1987), undoubtedly because these procedures require less deep pulpal anesthesia (Handler and Albers1987; Walton1990).

● The poorest results are observed with endodontic proce-

dures (Malamed 1982; Faulkner 1983; Kaufman etal.1983; Miller1983; Grundy1984) and tooth cutting (Malamed 1982; Kaufman et al. 1983; Miller 1983) because these approaches require deep pulpal anesthesia.

2) Teeth in which a PDL injection is made. Thus, the worst

results are noted for the anterior teeth (incisors and canines) and the best results in the posterior teeth (molars and premolars) (Kaufman etal.1983; White et al. 1988; Meechan2002). These data are also shown in Table18.3.

3) The clinician’s experience with this technique also

improves on the results of clinical trials (Grundy1984).

Instrument Set

The PDL technique can be performed with the traditional instrument set or with a more specific set, which is worthy of analysis in terms of both syringes and needles.

Syringes

1) Traditional syringe. This is the classic cartridge- type

metal syringe, although it has certain disadvantages with respect to the PDL technique: (i) it exerts half the pressure of a high-

pressure syringe (pistol- type) (Table18.2), therefore its anesthetic effect is reduced (Table18.1) given that pressure is a key factor for the success of this technique; (ii) women tend to exert 30% less pressure than men with the traditional syringe (Walmsley etal.1989); and (iii) if the cartridge breaks because of excess pressure, the syringe does not have the security foil that high- pressure syringes have to prevent glass fragments from falling into the patient’s mouth (Malamed1982; Miller1983).

2) Pen- type high- pressure syringe (Citoject®) (Figure18.3).

This type of high- pressure syringe is easier to hide in the hand, with the result that it is less “threatening” for the patient (Primosch1986), although it is less stable and requires considerable pressure with the fingers (Cowan1986). Each trigger pull injects 0.06 ml. In terms of clinical efficacy, this syringe is 65% successful as a primary technique (Cowan1986).

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Table18.3 Percentage ofpulpal anesthesia, evaluated using anelectrical pulp tester, after administration ofthe standard solution

(L-

100) withthe PDL technique anda high- pressure pistol- type syringe inthe maxillary teeth (max) andmandibular teeth (mand).

Adjacent teeth

Tooth Reference Sample size Pulpal anesthesia Duration (min) Mesial Distal

Molars and premolars (M and PM)

First M max White etal. (1988) 20 75% 7 45% 60% First M mand White etal. (1988) 38 79% 6 33% 62%

Cohen etal. (1993) First PM max White etal. (1988) 24 58% 4 17% 42% First PM mand Handler and Albers (1987) 7 57% 22 —

Moore etal. (1987) 19 79% 10 16% 63%

Schleder etal. (1988) 75 87% 20 45% 78%

White etal. (1988) 39 63% 8 21% 45%

McLean etal. (1992) 24 38% 12 —

Meechan (2002) 16 79% 16 — — Second PM D’Souza etal. (1987)

Incisors and canines (LI, C)

C max Johnson etal. (1985) 20 35% 10 — — LI max White etal. (1988) 23 39% 16 30% 26%

Kaufman etal. (1994) 40 50% 5 —

Meechan (2002) 16 75% 16 — — LI mand White etal. (1988) 22 18% 7 9% 9% C max Johnson etal. (1985) 20 55% 17 —

10 80% — — —

—

42 60% — — — Average 68.6% 11.7 30% 58% Rounded average 70% 10

—

Average 45.3% 11.8 20% 18% Rounded average 45% 10

The table also shows the extension to adjacent teeth both mesially and distally. L- 100 is the standard solution of lidocaine 2% with epinephrine 1:100 000 (10 μg/ml).

Cold stimulus with dichlorodifluoromethane in irreversible pulpitis, instead of an electric pulp tester.

Cold stimulus with carbon dioxide, instead of an electric pulp tester.

Figure18.3 High- pressure pen- type syringe (Citojet®).

3) Pistol- type high- pressure syringe (Ligmaject® and

Peripress® or similar syringes) (Figure18.4).

This type of syringe first appeared in the 1970s. It has a pistol grip and a barrel with a lateral window that enables the clinician to see how much solution remains in the cartridge and any possible breakage in the cartridge (Primosch 1986). The syringe has a Mylar sheath that encases the cartridge in the barrel to prevent pieces of glass from entering the patient’s mouth in the case of breakage (Khedari1982; Malamed1982; Miller1983; Saadoun and Malamed1985; Primosch1986). It is important to remember that with this technique the cartridge can break in 1.5%

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● Tooth (pulp and periodontal ligament) on which the

technique is performed, extending mesially– and more often distally– to the adjacent teeth.

● Vestibule and tongue area, both the fibromucosa (alveo-

lar mucosa, gum, and interdental papillae) and the bone and periosteum of the anesthetized tooth. It is important to remember that this technique is applied in a very welldefined area.

Figure18.4 High- pressure pistol- type syringe (Ligmaject® or

Peripress®).

of cases (Primosch1986). Each trigger pull injects 0.2 ml of the anesthetic solution (Council on Dental Materials, Instruments, and Equipment1983).

The pistol grip provides better control and stability, thus enabling the following: (i) application of considerable pressure (Chenaux et al. 1976; Khedari1982; Pashley 1986; D’Souza et al. 1987), almost twice that of a traditional syringe (Table 18.2), and (ii) a measurable difference in applied pressures between male and female providers has not been detected (Walmsley etal. 1989). Therefore, as a primary technique, this type of syringe has a success rate of 75% (Table18.1).

Needles

Traditional cartridge- type syringes require 27G or 25G short needles (20–25

mm). Since 25G needles are more rigid, they are easier to manage (Walton and Abbott1981; Malamed1982; Walton1990).

High-

pressure syringes require 30G or 27G extrashort

needles (8–12

mm), and although the 30G needle is the most widely used, it is also the caliber that most frequently bends under the pressure applied during injection (Malamed 1982; Smith and Smith 1983a). Therefore, the extrashort 27G needle (8 mm) is preferable, since it bends less and is sufficiently fine to fit between the tooth and the alveolar crest.

Cartridges

Glass cartridges are preferred because they can bear twice as much pressure as plastic cartridges before breaking (Table18.2). Plastic cartridges do not break, although they deform at half the pressure of a glass cartridge, thus enabling the anesthetic solution to leak out (Meechan etal.1990).

Anesthetized Area

The area anesthetized with the PDL technique is welldefined, as in all supplementary techniques.

Technique

● If a dental dam is in place, then it must not be removed

(Nusstein etal.2003). This is an advantage.

● As a primary technique, this approach is considered

painful (Annex 23), but it is not painful in practice because it is used as a supplementary technique when all other approaches have failed and therefore all the adjacent tissues, but not the dental pulp, are anesthetized.

● Given our previous comments, the most advisable

approach would be to use a pistolsyringe with an extrashort 27G needle (8

type high- pressure

mm) and a local anesthetic solution with epinephrine (if there are no contraindications), similar to the one being used in the area (remember not to mix two different anesthetic solutions at the same site). For example, if articaine 4% with epinephrine 1:100

000 (A- 100) is used in a buccal maxillary infiltration, then the same solution should be injected; if a mandibular block is performed with standard lidocaine 2% with epinephrine 1:100 then reinforced with a buccal infiltration a of Athen the procedure should be continued with A-

000 (L- 100) and

100,

100 in

the intraligamentary technique.

● Clean the gingival area of food particles, debris, plaque,

or tartar beforehand (Chenaux et al.1976; Brännström et al. 1982; Kaufman et al. 1983; Council on Dental Materials, Instruments, and Equipment1983; Faulkner

1983) to prevent them from entering the tissues.

● Insert the needle into the gingival sulcus. This is the

most important step, and often the most difficult (Council on Dental Materials, Instruments, and Equipment1983).

○ Insert the needle mesially into the mesial- buccal and

mesial- lingual angles, distally into the distal- vestibular and distal- lingual angles (Figure18.5).

○ With an angle of approximately 30° with respect to the

axis of the tooth to respect the convexity of the enamel of the neck of the tooth (Figure18.6).

○ The bevel should be facing outwards. ○ The needle should be forced firmly between the alveolar

crest and the cervical surface of the root of the tooth, pressing toward the apex.

○ It is occasionally necessary to bend the stem of the

needle to reach the most posterior teeth (Chenaux etal.1976; Khedari1982; Primosch1986).

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Figure18.5 Mesio- vestibular, mesio- lingual, disto- vestibular,

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and disto- lingual angles where the needle is inserted.

30°

Figure18.6 30° angle with respect to the axis of the tooth for

insertion of the needle. Note that the bevel is turned outwards.

● Aspiration is not necessary since the anesthetic solution,

once injected, is thought to reach the systemic bloodstream quickly (Smith and Walton1983b; Rawson and

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Orr II1985). Some clinical trials report positive aspirations in 94% of cases (Medvedev etal.2012).

● Inject under pressure.

○ Pressure is very important for the success of the tech-

nique and is a sign that the needle has been inserted correctly (Walton and Abbott 1981; Smith and Smith1983a). If the injection is made at several points in a tooth, then there should be resistance to the injection in at least one point. If there is no resistance, then the anesthetic solution has been distributed through the soft tissue but has not reached the apex.

○ If there is no resistance, remove the needle and reposi-

tion it by reinserting it and forcing it toward the apex (Khedari1982).

○ Pressure should be maintained at each point for

10–20

seconds while injecting slowly (Meechan1992) in

order to:

◼ Prevent excess pressure from breaking the cartridge. ◼ Ensure that the anesthesia penetrates the tissue,

preventing reflux of the anesthetic into the mouth. Despite these measures, some of the anesthetic often flows back into the patient’s mouth, and in 70% of cases he/she notices the bitter taste of the solution (Grundy1984).

○ The gum adjacent to the injection point turns white

and pale owing to the ischemic effect of the pressure and the vasoconstrictor.

● Amount to be injected. ○ Each trigger pull injects 0.2 ml (Chenaux etal.1976;

Council on Dental Materials, Instruments, and Equipment1983). Thus:

◼ In monoradicular teeth, the solution is injected into

one or two of the abovementioned sites mesially and/or distally (total 0.2–0.4 ml).

◼ In the case of multirooted teeth, the solution is

injected at two or four sites mesially and distally (total 0.4–0.8 ml).

○ These amounts are indeterminate since an unknown

quantity of solution flows back into the patient’s mouth.

● Onset of pulpal anesthesia is very fast (10–30 seconds)

(Walton and Abbott1981; Kaufman etal.1983; Gray and Rood1987; White etal.1988; Childers etal.1996). In 93% of cases where anesthesia is successful, the pulp is already anesthetized at 15 seconds (Walton and Abbott1981). The anesthetic effect has a short duration, on average 10 minutes (Table18.3) and generally less than 20 minutes (Childers etal.1996).

○ As the effect is very localized and there are scarcely

any subjective symptoms (soft tissue anesthesia), the only guarantee of success is treatment. If the technique is used as a supplementary approach (the most common situation), the soft tissue anesthesia is from the techniques that have failed.

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○ As primary anesthesia (very uncommon), anesthesia of

the soft tissues lasts 25–40

● If the approach fails, a new attempt can be made after

30–60

seconds (Cohen etal.1993), thus improving the

minutes (Johnson etal.1985).

results (Table18.4). There is generally no risk of toxicity, even though the technique is considered to inevitably result in intravascular administration, since the dose administered is small and the technique is only used in specific teeth when standard techniques have failed. Moreover, part of the injected solution flows back into the mouth.

Efficacy ofThis Technique

The efficacy of the technique is evaluated using an electric pulp tester, which tells us that the success rate is 70% in posterior teeth and 45% in anterior teeth, with a duration of around 10

minutes (Table18.3). These data are for pistoltype high- pressure syringes and a single injection of standard solution (L-

100). Furthermore, we can observe that the neighboring teeth are also anesthetized, especially the distal teeth (Table18.3). Evaluation of clinical success (more subjective and less rigorous method) reveals a success rate of 90%, although this can be with one or two injections (two if the first fails) (Tables18.4 and18.5).

Table18.5 Percentage ofclinical success withthe periodontal

ligament injection using apistolinjection solution (L-

Reference Sample size Treatment Success

Malamed (1982) 100 Ob, Ex, En, C 86% Faulkner (1983) Kaufman etal. (1983) 258 Ob, Ex, En 84% Miller (1983) 361 Ob, Ex, En, C 96% Smith and Smith

(1983a) Matthews and

Stables(1985) Rakusin etal. (1986) 30 Ob 97% Gray and Rood (1987) 48 Ob, Ex, En 92% Edwards and Head

(1989)

L- 100, lidocaine 2% with epinephrine 1 : 100 000; Ob, obturation; En, endodontics; Ex, extraction; C, cutting. Success after one or two injections.

Local anesthetic solution unknown.

100).

type syringe andthe standard

200 Ob, Ex, En 86%

60 En 85%

100 — 86%

14 Ex 80%

Average 88%

Rounded average 90%

Specific Complications ofthe Technique

Complications Dueto Performance ofthe Technique

1) 30G needles usually bend because they are not very

rigid and it is necessary to apply a certain degree of pressure (Malamed 1982; Kaufman etal. 1983; Smith and Smith 1983a), therefore it is more appropriate to

Table18.4 Percentage ofsuccessful clinical outcome after

thefirst injection andafter thefirst andsecond injections, both withpistol-

Reference Treatment

Smith and Walton (1983b)

Gray and Rood (1987)

Cohen etal. (1993) En 80% 90% Cohen etal. (1993) En 70% 100%

Ob, obturation; En, endodontics; Ex, extraction.

type syringes.

First

injection

En 65% 85%

Ob, Ex, En 71% 92%

Average 72% 92% Rounded average 70% 90%

Success

First and second

injection

use extrashort 27G needles in high-

pressure syringes because these are more rigid and resistant. If the needle bends, it should be replaced.

2) Reflux of the anesthetic solution into the patient’s

mouth is common. The patient experiences the bitter taste in the case of solutions that contain vasoconstrictor (Malamed1982; Kaufman etal.1983). This occurs in 70% of cases in some series (Primosch1986).

3) Breakage of a glass cartridge due to excess pressure

(Malamed1982; Kaufman etal. 1983). This has been reported in 1.5% of cases (Primosch1986). Thus, with traditional cartridge-

type syringes, pieces of glass may fall into the patient’s mouth (especially if the cartridges do not have a transparent adhesive plastic protective sleeve [security foil] that limits splintering; Rawson and Orr II1985). The problem of glass entering the patient’s mouth does not affect the high- pressure syringes used in the PDL technique because they have a transparent plastic sleeve that encases the cartridge in the barrel of the syringe (Khedari1982; Malamed 1982; Miller1983).

Periodontal Abnormalities

The periodontium can be damaged for three reasons (Brännström etal.1982; Peterson etal.1983): (i) mechanical damage caused by the needle, (ii) pressure of the injected solution, and (iii) toxic effect of the solution.

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Studies with animals (mainly dogs and monkeys) and gum dissection have shown lesser damage, mainly in the bony crest and cementum and in the more coronal areas, with reabsorption of the root (Roahen and Marshal 1984, 1990; Nakane and Kamayama1987). This type of damage reverses in a few weeks (Brännström et al.1982; Walton and Garnick1982; Dreyer et al.1983; Fuhs et al.1983; Peterson et al. 1983; Galili et al. 1984; Albers and Ellinger1988).

Clinical studies in humans have shown that there are no periodontal sequelae after a few weeks (Malamed 1982; Moore etal.1987; Schleder etal.1988). However, complications and exceptional cases may arise, as follows:

1) Pain after a PDL injection is very common (Kaufman

etal.1984; D’Souza etal.1987) and occurs in around 80% of cases (Schleder etal.1988; White etal.1988; Nusstein etal.2004). It is very intense in 5% of cases (Table18.6), although it usually resolves spontaneously in 2–3 days.

2) Twenty percent of patients report feeling that the tooth

is high during occlusion (Table 18.6), although this resolves spontaneously in a few days. If the feeling does not improve, occlusion can be adjusted (Malamed1982). There have been reports of two extreme cases of teeth that were ejected after the PDL injection: a first mandibular premolar (Nelson 1981) and a mandibular molar (Council on Dental Materials, Instruments, and Equipment1983), both of which were healthy.

3) A certain degree of gingival inflammation appears in 5%

of cases (Table18.6). This resolves spontaneously in a few days, and, if it lasts longer, chlorhexidine mouth rinses and antibiotics can be administered. Three extreme cases have been reported: an upper molar with recession of the root that required endodontic treatment (White etal.1988), a molar with marginal papillitis and necrosis (Kaufman et al.1983), and a molar with inflammation of the gum, loss of 50% of bone, and pockets measuring 6–8 mm treated with scaling and root planning and antibiotics for 8 months (Childers etal.1996).

Pulpal Abnormalities

Dissections of teeth in experimental animals revealed no histological changes or damage in dental pulp (Roahen and Marshall 1984, 1990; Peurach 1985; Albers and Ellinger1988; Walton1990; Plamondon et al.1990). The same observation was reported for humans (Torabinejad etal. 1993). Some experimental studies revealed reduced pulpal blood flow due to the action of epinephrine in the injection (Kim1986).

Clinical studies in humans have not reported pulpal abnormalities (Malamed1982; Moore etal.1987; Schleder etal.1988), except for the case of pulpal abnormality in a cut tooth (Kim1986). We do not know whether the PDL or the cutting caused the problem.

Table18.6 Percentage ofperiodontal complications withthe periodontal ligament injection.

Reference Sample size Severe postinjection pain High tooth feeling Gum inflammation

Malamed (1982) 100 3% 2% — Kaufman etal. (1983) 258 2% — 0.4% Faulkner (1983) 200 — Grundy (1984) 361 9% — — Matthews and Stables(1985) 100 11% — — Johnson etal. (1985) 20 — — 5% Rakusin etal. (1986) 32 10% — Davidson and Craig (1987) 100 8% — — List (1988) 22 — 27% — Schleder etal. (1988) 75 5% 49% 5% Spuller (1988) 28 — White etal. (1988) 147 2% — — McLean etal. (1992) 48 2% 13% — Nusstein etal. (2004) 51 3% 27% 8%

Average 5.5% 20.2% 4.2% Rounded average 5% 20% 5%

— 2.5%

—

3.5% —

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328

Cardiovascular Abnormalities

The PDL technique is considered almost intravenous since the anesthetic solution passes very quickly to the bloodstream. Experiments with dogs revealed a 20% fall in arterial pressure and a 20% increase in heart rate (Smith and Pashley1983d; Pashley1986).

Clinical trials with anesthetic solutions containing epinephrine 1:100 Nusstein etal. 2004) and 1:80

000 (10 μg/ml) (Kaufman et al. 1994;

000 (12.5 μg/ml) (Gray and Rood 1987) did not reveal appreciable modifications in arterial pressure or heart rate. However, the use of higher concentrations of epinephrine (1:50

000, 20 μg/ml) leads to an increase in heart rate (tachycardia), which patients describe as palpitations, in 20% of cases (Kaufman etal.1984).

Intraseptal Technique

The intraseptal technique, also known as the crestal technique (Giffin1994) or papillary technique (Marthaler1970), involves inserting the needle into the interdental papilla to reach the septum (where the cortical plate is very narrow or has disappeared [Marthaler1970] and which is the exit for a large number of miniperforations that finish in the medullary cavity [Saadoun and Malamed1985]) and penetrating a few millimeters with the tip of the needle to inject the anesthetic solution under pressure into the cancellous bone so that it spreads quickly to the apex of the tooth. In practical terms, this approach is a variant of the PDL injection; in addition, during the PDL injection, the needle very often becomes stuck in the alveolar crest instead of in the gingival sulcus, and the solution is injected into the interdental septum under pressure.

The intraseptal technique was already well known in the 1940s (Nevin and Puterbaugh1949). It was recovered by Marthaler in the 1970s (Marthaler1970).

Factors Underlying aSuccessful Technique

1) The use of pistol- type high- pressure syringes, such as

those used in the PDL (Ligmaject® or Peripress®), because they enable high- pressure continuous and uniform injection (Saadoun and Malamed1985).

2) 27G extrashort needles (8–12 mm), which are some-

what thicker than the 30G needles, since these are sufficiently rigid so as not to bend during injection under pressure and sufficiently fine to penetrate the intraseptal bone (Saadoun and Malamed1985; Giffin1994).

3) The use of local anesthesia solutions with vasoconstric-

tor, such as lidocaine 2% with epinephrine 1:100 000 (Giffin1994) or 1:50 000 (Saadoun and Malamed1985).

Contraindications

The contraindications are the same as those of the PDL technique, as follows:

1) In primary teeth, there is a risk of permanently damag-

ing the tooth (Alantar1993).

2) In the case of teeth with advanced periodontal disease,

the periodontal structures may be affected. This point is under debate because some authors consider it a contraindication (Alantar 1993), whereas others do not (Saadoun and Malamed1985). As is the case with the PDL injection, teeth affected by periodontal disease that are to be extracted constitute an exception.

3) Infection at the injection site.

Anesthetized Area

● Tooth (pulp and periodontal ligament) on which the

technique is applied, although the area anesthetized frequently extends to the adjacent teeth mesially and distally. The results are not known with any degree of accuracy, although they are considered to be similar to those of the PDL technique (Giffin 1994), with a lower percentage of success in the anterior teeth (Giffin1994) and a shorter duration of pulpal anesthesia.

● Vestibule and lingual area, both in the fibromucosa

(alveolar mucosa, gum, and interdental papillae) and in the bone and periosteum along a limited band measuring approximately 20–25

mm in length (Saadoun and

Malamed1985). Anesthesia lasts less than an hour.

Technique

● Select the insertion site in the center of the interdental

papilla close to the tooth to be anesthetized. The inser-

tion site is at the midpoint of the papilla between the teeth and exactly 2

● Place the needle vertically at an angle of approximately

mm under the cusp of the papilla.

45° with respect to the axis of the tooth and horizontally perpendicular to the papilla (Figure18.7).

In posterior mandibular teeth, it may be necessary to bend the needle some 45° along the stem to ensure correct positioning.

● Insertion of the needle: ○ Inject a few drops into the fibromucosa of the papilla

after inserting the needle.

○ Advance the needle until it makes contact with the

alveolar bone crest and continue to apply pressure so that the needle crosses the weak point of the cortical plate at this level and reaches the cancellous bone. In

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45°

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Figure18.7 Insertion of the needle into the interdental

septum at an approximate angle of 45°, with penetration of the

cancellous bone.

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● Aspiration is not performed, since this technique,

as with the PDL injection, is considered almost intravascular.

● Anesthesia is almost immediate, less than 15 seconds

(Saadoun and Malamed1985). It is restricted to the tooth and the surrounding area, and the patient has no subjective sensation of paresthesia in the soft tissues. If anesthesia has not been achieved after 30

seconds, then the technique has failed and must be restarted (Saadoun and Malamed1985).

Specific Complications ofthe Technique

1) Pain during the injection in more than 25% of cases,

when it is used as the primary technique (Saadoun and Malamed 1985), although in practice it is used as a supplementary technique in cases of failure, when the tissues are already anesthetized.

2) Patients often complain of palpitations (tachycardia)

owing to the use of anesthetic solutions containing epinephrine (Saadoun and Malamed1985; Giffin1994).

3) Postinjection pain at the injection site in 20% of cases,

although this disappears spontaneously in 1 or 2 days (Giffin1994).

total, the needle can penetrate 2–3 mm into the bone tissue (Figure18.7).

○ Withdrawing the needle 1 mm and rotating the syringe

helps the needle to penetrate the bone (Saadoun and Malamed1985).

● Inject 0.2–0.4 ml of anesthetic solution (Saadoun and

Malamed1985; Alantar1993; Giffin1994).

○ The solution is injected under pressure so that the anes-

thetic penetrates the medullary spaces. In addition, it is injected slowly (0.2 ml in 20–30 seconds) to prevent excess pressure from breaking the cartridge.

○ The ischemia caused by the pressure of the injection and

the vasoconstrictor in the solution leads to blanching.

○ If the injection is very fluid and there is no pressure,

then the needle is not penetrating the bone and the distribution of the solution is limited to the soft tissue or may even flow back into the mouth (in this case the patient notices the bitter taste of the solution [Saadoun and Malamed1985]). The needle should then be withdrawn and repositioned in the papilla before starting the procedure again.

○ If the injection seems difficult and the needle does not

advance despite pressure, then it has reached an area of thick cortex or is poorly angled, thus preventing it from entering the cancellous bone. In this case, the needle should be withdrawn and repositioned in the papilla before starting the procedure again.

Intraosseous Technique

This technique is also known as the intradiploic or transcortical technique. It involves crossing the cortex with a drill and using a needle to inject the anesthesia into the cancellous bone close to the tooth to be anesthetized in such a way that it spreads rapidly toward the apex.

The technique was first applied by Otte in 1896 (Smith 1920) or by R. Nogué in 1907 (Nogué 1907) (we were unable to verify which of the two was first) and then by Masselink in 1910 (Masselink1910). In these early techniques, the bone was perforated with round burrs (thus making it difficult to maintain the perforation straight) and the solution was injected with a thick cannula to prevent reflux (Masselink 1910; Parrot1914). During the 1930s, the method became popular and dentists started to drill at the level of the attached gingiva with straight burrs (Schmitt1936; Nevin and Puterbaugh1949). In the 1940s, Beutelrock perforators became popular; however, as these were relatively long, they broke easily, and it was difficult to extract them (Nevin and Puterbaugh1949). Consequently, the Van den Berg system was developed (Leonard 1995; Dunbar etal.1996; Peñarrocha et al. 1997); this involved 5- mm perforators with a stop to prevent overpenetration and extrashort needles of the same caliber. Unfortunately,

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330

the perforator was too short (5 mm) and, very often, it was not possible to completely perforate the cortical plate (Roberts and Sowray1987). During the 1960s and 1970s, few studies based on this technique were published (Magnes1968; Bourke1974; Lilienthal1976).

The modern era began in 1991, when Frank Dillon devel-

oped the Stabident designs and disposable materials, with a 9-

system, which incorporated new

mm drill and a needle of the same caliber and length (Leonard 1995; Dunbar etal.1996; Peñarrocha etal.1997). Later, in 1999,

Arthur Weather developed the X-

system, with charac-

Tip

teristics that are very similar to those of Stabident® but which incorporates a guide sleeve so as not to lose the perforation when inserting the needle (Hawkins and Moore2002). Some time later, Stabident® also incorporated an optional guide sleeve. Other less popular variants began to appear, such as a hand-

held device designed for this technique, IntraFlow® (Kleber2003; Remmers etal.2008) or Anesto (Graetz et al. 2013), and the hybrid system known as QuickSleeper (Villette2003) (see Chapter20).

In this section, we provide a careful analysis of the

Stabident® and X-

Tip® systems because these are the most

important and most widely used.

Indications, Contraindications, andDisadvantages

We have already mentioned the indications. The intraosseous technique is a supplementary technique that is only used when standard techniques fail. In addition, it has two disadvantages: (i) it requires a perforator and an extrashort needle, and (ii) rubber dams must be removed to apply the technique (one advantage of the PDL injection is that this is not necessary). The contraindications of the technique are as follows:

Instrument Set

In this section, we analyze the instruments used in the two main systems, Stabident® and X-

Stabident®

Tip®.

This system is based on two elements, as follows (Stabident instruction manual2001) (Figure18.8):

1) The perforator, or drill, which comprises a plastic shank

and has the following parts:

○ Plastic shank that is inserted into the contra- angle

hand piece.

○ Plastic stop that marks the depth of perforation and

is, at the same time, an adapter for the plastic protective cap that covers the metal needle of the perforator.

○ Solid 27G metal needle (0.43 × 9 mm) that comes out

of the plastic stop and is the active part of the perforator used to penetrate the cortical layer.

○ Plastic protective cap that covers the solid metal nee-

dle (or active end) and adapts to the plastic stop.

2) Extrashort 27G needle (0.4 × 8 mm) with dimensions

that are identical to those of the perforator and covered by its corresponding sleeve.

The instrument is sufficiently long to cross the gum and cortical bone, and thus reach the cancellous bone in most cases. Table18.7 shows the thicknesses to be crossed by the perforator. Since the distance would be greater than 8

mm in only 2.5% of cases, the system has a longer reach than the 5

mm of the old Van den Berg system.

1) Primary teeth, since the permanent tooth buds may be

damaged, although some authors have used the approach in children (Magnes1968; Bourke1974).

2) Teeth with advanced periodontal disease since the tooth

may fall out accidentally during the procedure (Parente etal.1998). Teeth to be extracted are an exception.

3) Infection with cellulitis or an abscess in the area to be

perforated since this would be very painful and deep anesthesia may not be achieved (Reader et al. 2011; Council on Clinical Affairs2015).

4) Areas with little cancellous bone, such as those between

the upper and lower central incisors (Lilienthal1975a) and areas with very crowded teeth. As it is difficult to drill in these areas, it is recommended to use the nearest distal space. An alternative is to use the PDL injection and not the intraosseous technique.

Figure18.8 Stabident® system with the perforator (1) and

needle (2).

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